This triptych is painted on the subject of God’s appearance in Good, Truth and Beauty.
Blue angel in the middle is guarding the Truth. He’s namely guarding it, because the Divine Truth exists from times immemorial, but it’s necessary to guard it: firstly, in order not to let it fade, and secondly - from imprudent utilization, so as not to burn something. The Truth in inaccurate hands is dangerous.
On the right is Scarlet angel - the one who is carrying the Good. At that the highest good is self-determination, since the source of good is then being carried inside, man becomes self-sufficient, and the symbol of the victory over oneself is a palm frond.
On the left from the Blue angel there is a half-transparent Emerald colour angel, who is liberating a beautiful flower - a rose. He is just called so - Liberating the Beauty, since Beauty is a quite earthly value: in Paradise everything is beautiful, while for hell beauty is more terrible than sulphuric acid. But in our earthly world Beauty is a self-acting force: not for vain had Dostoyevsky written that it would save the world. Emerald colour (the colour of artificial) means that before beeing liberated Beauty needs to be created